#include "frontieregraphicsfleche.h"
#include "etat.h"
#include "frontiere.h"

#include <QtGui>
#include <math.h>

static const double Pi = 3.14159265358979323846264338327950288419717;
static double TwoPi = 2.0 * Pi;

FrontiereGraphicsFleche::FrontiereGraphicsFleche(Frontiere *frontiere) :
    FrontiereGraphics(frontiere), arrowSize(5)
{
    adjust();
}

void FrontiereGraphicsFleche::adjust()
{

    if (!frontiere->sourceEtat() || !frontiere->destEtat())
        return;

    QLineF line(frontiere->sourceEtat()->pos(), frontiere->destEtat()->pos());

    qreal length = line.length();

    prepareGeometryChange();

    if (length > qreal(20.)) {
        QPointF edgeOffset((line.dx() * 10) / length, (line.dy() * 10) / length);
        sourcePoint = line.p1() + edgeOffset;
        destPoint = line.p2() - edgeOffset;
    } else {
        sourcePoint = destPoint = line.p1();
    }
}

QRectF FrontiereGraphicsFleche::boundingRect() const
{
    if (!frontiere->sourceEtat() || !frontiere->destEtat())
        return QRectF();

    qreal penWidth = 1;
    qreal extra = (penWidth + arrowSize) / 2.0;

    return QRectF(sourcePoint, QSizeF(destPoint.x() - sourcePoint.x(),
                                      destPoint.y() - sourcePoint.y()))
        .normalized()
        .adjusted(-extra, -extra, extra, extra);
}

void FrontiereGraphicsFleche::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
    if (!frontiere->sourceEtat() || !frontiere->destEtat())
        return;

    QLineF line(sourcePoint, destPoint);
    if (qFuzzyCompare(line.length(), qreal(0.)))
        return;

    // Déssine la ligne
    painter->setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));
    painter->drawLine(line);

    // Déssine la fleche
    double angle = ::acos(line.dx() / line.length());
    if (line.dy() >= 0)
        angle = TwoPi - angle;

    QPointF sourceArrowP1 = sourcePoint + QPointF(sin(angle + Pi / 3) * arrowSize,
                                                  cos(angle + Pi / 3) * arrowSize);
    QPointF sourceArrowP2 = sourcePoint + QPointF(sin(angle + Pi - Pi / 3) * arrowSize,
                                                  cos(angle + Pi - Pi / 3) * arrowSize);
    QPointF destArrowP1 = destPoint + QPointF(sin(angle - Pi / 3) * arrowSize,
                                              cos(angle - Pi / 3) * arrowSize);
    QPointF destArrowP2 = destPoint + QPointF(sin(angle - Pi + Pi / 3) * arrowSize,
                                              cos(angle - Pi + Pi / 3) * arrowSize);

    painter->setBrush(Qt::black);
    painter->drawPolygon(QPolygonF() << line.p1() << sourceArrowP1 << sourceArrowP2);
    painter->drawPolygon(QPolygonF() << line.p2() << destArrowP1 << destArrowP2);
}

